car went **** up a few weeks ago, lost power then a few minutes later developed a misfire, got the car into work last week and set about sorting it.

checked the obvious and eventually found a dead coilpack, while it was all apart we changed the cambelt and tensioners as the old belt was looking tired and we couldnt quite get the marks to line up with it.

got the new belt on and finished last night and the car started spot on running smoother and queiter than ever.

now here's the problem the exhaust is VERY quiet and the turbo will not produce any boost?? no undue noises when driving and do get small amounts of wastegate chatter when approaching zero on the guage.

swapped the solenoid, tried another turbo, took the exhaust off to see if its clear, checked all hoses even run the actuator pipe direct from the turbo and still nothing. done a compression check and got over 150 on all four cylinders. As said the engine runs lovely just very slow..it doesnt pick up very well through the rev range and just sounds off when i try to push it to make any boost.

i'm lost for things to try now.

 

header leak, boost leak (intercooler pipe, vac hose, dump valve, intercooler split), wastegate stuck open, actuator fubar...

usual step though..

Simon

 

wastegate flutter, could either be dv is stuck/duff, vac line to it, actuator stuck as simon said, or vac lines to from WG solenoid.

 

good point,. if you can hear flutter as the boost gauge reaches 0 (you have checked the boost gauge is correct?) then it is possible the turbo is producing the boost and is overspeeding trying to produce more due to a boost leak somewhere.

Simon

 

there's no dumpvalve on the car, all pipes have been checked, actuator and wastegate are fine (on both turbo's) there's no noise from a boost leak and cant hear the turbo spool up and the exhaust is like silent runnings now compared to how it was, it all points to a dead turbo but it isnt???

 

inlet hose collapsed ?

 

we pretty much stripped and checked the whole system, everything looks and feels ok, the car drives fine just cant see why it wont make any boost

 

cat or exhaust sliencer collapsed

 

cars not got a cat and its a 3" system turbo back, we've had the exhaust off and its clear, changed the maf and tried a stock ecu and still no difference, if i drive at very light throttle it pulls ok and seems to get 2-3 psi boost but as soon as i open the throttle the engine note changes and boost drops off and the engine really struggles to rev at all, it drives well upto 3.5k and nothing afterwards

 

Re-check your coil packs, plugs and connections again if you have already.

 

done all of that mate i'm lost for things to check now, found one dead coil swapped that and it cured the misfire but still got no power

 

Have you tried the water temp sender

 

cel is showing no codes and it makes no difference to the running if the engine is hot or cold

 

boost leak.. what it sounds like.. a jubliee clip tight on itself but not on the pipe and enough to leak but pipe not blow off on boost..

 

did u leave engine in car to do cam belt?? Obviously as a observation if it was boosting before but not now you have disturbed a boost pipe. but by the sounds you have taken all parts of.. check pipe to boost gauge??

 

cam belt changed with engine in car normally

 

the car lost power very suddenly before the belt was done, i am getting a little bit of boost in lower gears 2-3 psi at light throttle but the engine sounds so flat and struggles to rev freely past 4k especially in 5th, bearing in mind how loud my car normally is, at motorway speed now its like the car it switched off its that quiet now. the cel is still showing no codes and i'm still checking everything over and over with no joy as to finding whats wrong

 

checked and checked the hoses simon, there's no noise of a boost leak anywhere and the cars not smoking at all.

are there any other engine sensors that might kill boost if they're not working?

 

is it running on 4 cylinders?

 

yep perfectly now the coil pack has been changed, done a compression check and got good even pressure all round

 

I’m assuming you didn’t test the car after replacing the coil pack to see if that actually fixed the first problem? It’s possible that replacing the cam belt has in fact introduced another as it sounds as if your timing may be running retarded.

 

compression on cylinders wouldn't be even if cambelt was wrong

Simon

 

May sound silly and obvious....but have you checked the spark plugs?

Its cant be a sensor as otherwise the ECU would have thrown a CEL by now....so its back to basics again....what ecu is your car running?

Have you made any further checks on this?

 

That depends on how much thought you give to this. Given the OP had the issue after replacing the belt and not before and has also tried all the above and more, its worth a look. If it's ok, move on

 

All fixed, after taking it off again and re checking it turns out the second silencer on the exhaust had completely destroyed itself, removed all the debris and the car is back on song (just really really loud) annoying really as i'd already checked the exhaust and it looked fine but after a few days of driving it seemed to push all the blockage to the back. just need a quieter exhaust now.

 

sorry Neil you seem to have taken offence.. you may have missed his mention of compression test and given the OP has spent a fair bit of time trying to find the issue I didn't see not mentioning that with 150psi on all four cylinders it is not possible for the cambelt to be wrong.. no matter how much thought is put into it, it won't change the fact that with four cams any jump of a tooth or more anywhere (although they usually jump on the crank) will show in a compression test.. usually the compression drop from this is obvious on idle and cruise and on boost it is fine because it is only on one bank is drops.. completely the opposite of the problem described which turned out to be as mentioned 10days ago

Simon

 

Simon, i didnt take offence nor do i, you must have mistaken the for a . Here's some love instead

Pleased the OP is back on track.

Neil

 

i would do a ecu reset on it disconect battery for a hour then drive and let it relearn it may be stuck in limp mode do to fault steve

 

What sort of compression difference would there be between the banks if a cam *had* jumped a tooth?

 

Big drop to 60odd psi on one bank last one I saw iirc correct.
The crank had jumped 2teeth so left bank was 2 out and right bank correct